1. Field of the Invention
The invention relates to facing heads and refers more specifically to a facing head having a minimum axial dimension beyond the mounting surface thereof and which is capable in one embodiment of simultaneous boring and facing operations. The facing head includes slides movable transversely thereof which are biased in one direction in all positions thereof and structure for lubricating the facing head and/or passing coolant therethrough during rotation thereof.
2. Description of the Prior Art
In the past, facing heads have been unnecessarily extended from the spindles to which they are attached, thus causing undue lateral stresses on the spindle bearings and within the facing head structure itself. Further, facing heads of the past have often included particularly complicated structure for effecting transverse movement of a cutting tool relative to the axis of rotation of the facing head, which has increased the cost of such facing heads and lowered their efficiency.
Similarly, where simultaneous boring and facing have been accomplished in the past with facing heads, the structure for effecting such combined operations has sometimes been built into or been formed by a part of the associated spindles and usually has been complicated and expensive and sometimes inefficient.
Prior facing heads have also often incorporated considerable backlash in the structure included therein for moving cutting tools transversely thereof which has prevented effective precision control of start and stop positions. More important, such backlash has often resulted in chatter of the cutting tools, shortening the life of the tools and cutting mechanism and often providing an undesirable finish on a machined workpiece. Prior facing heads have not included wear compensation structure therein. Also with such prior structures, an inconsistency in the finish of the work has also occurred during the transition which occurs when the center of gravity of the slide combined with any objects fastened to it crosses over the balance center of the facing head assembly.
Further, in the past lubrication of facing heads usually has not been possible during operation of the heads, and lubrication in the past has been a manual operation. Coolant has usually not been supplied to a workpiece through prior facing heads.